Nicknamed "King Kong", Korab made a solid reputation for himself in the tough 1970's-era NHL as an imposing physical defenseman. His size gave him a distinct advantage in his own zone, and he also possessed a hard shot and some offensive skill.

Making his NHL debut with the Chicago Blackhawks in 1970-71, Korab was asked to simply keep the front of his own net clear, a task he was more than capable of handling. He continued to play the same role for the next two seasons while scoring 12 goals in 1972-73 and helping Chicago reach the Stanley Cup finals in 1971 and 1973.

Korab's best years were spent on the blueline of the Buffalo Sabres from 1973 to 1980, where he blossomed into an effective defenseman on one of the best young teams in the league. Korab was a physical presence while hitting double-digits in goals four times, helping the Sabres reach their first Stanley Cup final in 1975. He was picked to play in the 1975 and 1976 NHL All-Star Games.

Korab was traded to the Los Angeles Kings on March 10, 1980, for a first round draft choice that Buffalo used to select offensive defenceman Phil Housley. In 1983 he retired but two months into the season he was offered a chance to make a comeback with the Sabres. He would retire for good after playing 25 games with the Sabres in 1984-85.

Korab currently owns and operates Korab Inc., a packaging service located in Bellwood, IL.